A gas turbine provided with: an air cooler that subjects compressed air extracted from a compressor to heat exchange and supplies the cooled compressed air to a cooling system of a rotor system in a turbine; an air cooler bypass line that bypasses the compressed air introduced into the air cooler; an electric valve provided in the air cooler bypass line; and a control unit that controls opening and closing of the electric valve such that, during activation of a gas turbine, a degree of opening of the electric valve is set at or below a low-level degree of opening and such that, after the load of the gas turbine has been increased, the degree of opening of the electric valve is set to be larger than the low-level degree of opening.

A gas turbine provided with: an air cooler that subjects compressed air extracted from a compressor to heat exchange and supplies the cooled compressed air to a cooling system of a rotor system in a turbine; an air cooler bypass line that bypasses the compressed air introduced into the air cooler; an electric valve provided in the air cooler bypass line; and a control unit that controls opening and closing of the electric valve such that, during activation of a gas turbine, a degree of opening of the electric valve is set at or below a low-level degree of opening and such that, after the load of the gas turbine has been increased, the degree of opening of the electric valve is set to be larger than the low-level degree of opening.

An improved heat engine that includes an organic refrigerant exhibiting a boiling point below −35° C.; a heat source having a temperature of less than 82° C.; a heat sink; a sealed, closed-loop path for the organic refrigerant, the sealed, closed-loop path having both a high-pressure zone that absorbs heat from the heat source, and a low-pressure zone that transfers heat to the heat sink; a positive-displacement decompressor providing a pressure gradient through which the organic refrigerant in the gaseous phase flows continuously from the high-pressure zone to the low-pressure zone, the positive-displacement decompressor extracting mechanical energy due to the pressure gradient; and a positive-displacement hydraulic pump, which provides continuous flow of the organic refrigerant in the liquid phase from the low-pressure zone to the high-pressure zone, the hydraulic pump and the positive-displacement decompressor maintaining a pressure differential between the two zones of between about 20 to 42 bar.

An improved heat engine that includes an organic refrigerant exhibiting a boiling point below −35° C.; a heat source having a temperature of less than 82° C.; a heat sink; a sealed, closed-loop path for the organic refrigerant, the sealed, closed-loop path having both a high-pressure zone that absorbs heat from the heat source, and a low-pressure zone that transfers heat to the heat sink; a positive-displacement decompressor providing a pressure gradient through which the organic refrigerant in the gaseous phase flows continuously from the high-pressure zone to the low-pressure zone, the positive-displacement decompressor extracting mechanical energy due to the pressure gradient; and a positive-displacement hydraulic pump, which provides continuous flow of the organic refrigerant in the liquid phase from the low-pressure zone to the high-pressure zone, the hydraulic pump and the positive-displacement decompressor maintaining a pressure differential between the two zones of between about 20 to 42 bar.

Systems and methods for converting energy are provided. In one aspect, the system includes a closed cycle engine defining a cold side. The system also includes a bottoming-cycle loop. A pump is operable to move a working fluid along the bottoming-cycle loop. A cold side heat exchanger is positioned along the bottoming-cycle loop in a heat exchange relationship with the cold side of the closed cycle engine. A constant density heat exchanger is positioned along the bottoming-cycle loop downstream of the cold side heat exchanger and upstream of an expansion device. The constant density heat exchanger is operable to hold a volume of the working fluid flowing therethrough at constant density while increasing, via a heat source, the temperature and pressure of the working fluid. The expansion device receives the working fluid at elevated temperature and pressure and extracts thermal energy from the working fluid to produce work.

Systems and methods for converting energy are provided. In one aspect, the system includes a closed cycle engine defining a cold side. The system also includes a bottoming-cycle loop. A pump is operable to move a working fluid along the bottoming-cycle loop. A cold side heat exchanger is positioned along the bottoming-cycle loop in a heat exchange relationship with the cold side of the closed cycle engine. A constant density heat exchanger is positioned along the bottoming-cycle loop downstream of the cold side heat exchanger and upstream of an expansion device. The constant density heat exchanger is operable to hold a volume of the working fluid flowing therethrough at constant density while increasing, via a heat source, the temperature and pressure of the working fluid. The expansion device receives the working fluid at elevated temperature and pressure and extracts thermal energy from the working fluid to produce work.

The present invention provides a composition, such as a refrigerant composition comprising 1,1-difluoroethene (vinylidene fluoride, R-1132a); trifluoromethane (R-23); and one or more compound selected from hexafluoroethane (R-116), ethane (R-170) and carbon dioxide (R-744, CO.sub.2).

The present invention provides a composition, such as a refrigerant composition comprising 1,1-difluoroethene (vinylidene fluoride, R-1132a); trifluoromethane (R-23); and one or more compound selected from hexafluoroethane (R-116), ethane (R-170) and carbon dioxide (R-744, CO.sub.2).

Electrical/mechanical power is derived from oxycombustion of hydrocarbons, preferably LNG, in a first of two nested cycles each operating on a Brayton cycle to provide a source of power, without mixing of working fluids between the two cycles. Each cycle employs CO.sub.2 as a working fluid, the first cycle operating under low pressure conditions in which CO.sub.2 is sub-critical, and the other cycle operating under higher pressure conditions in which CO.sub.2 is supercritical. The first cycle serves as a source of heat for the second cycle by gas/gas heat exchange which cools the products of combustion and circulating working fluid in the first cycle and heats working fluid in the second cycle.

Electrical/mechanical power is derived from oxycombustion of hydrocarbons, preferably LNG, in a first of two nested cycles each operating on a Brayton cycle to provide a source of power, without mixing of working fluids between the two cycles. Each cycle employs CO.sub.2 as a working fluid, the first cycle operating under low pressure conditions in which CO.sub.2 is sub-critical, and the other cycle operating under higher pressure conditions in which CO.sub.2 is supercritical. The first cycle serves as a source of heat for the second cycle by gas/gas heat exchange which cools the products of combustion and circulating working fluid in the first cycle and heats working fluid in the second cycle.